At what point does a pathogen cross the threshold from dangerous nuisance to a threat to public health? The US Food and Drug Administration (FDA) wants to know, and the definition it decides on could have big implications for developers of antibiotic and antifungal products.

The question goes back to the July 2012 passage of the FDA Safety and Innovation Act(FDASIA), which contained a provision known as the Generating Antibiotic Incentives Now (GAIN) Act. GAIN amends the Federal Food, Drug and Cosmetic (FD&C) Act to include 505E, which takes a page from the development paradigm for orphan drug products by giving developers market-based exclusivity incentives if they develop products for a "qualified infectious disease."

Most-but not all-products would be eligible for a five-year extension of market exclusivity, as well as eligibility for priority review and fast track status, both of which would see FDA arriving at a decision more quickly than under normal circumstances.

So what is a "qualified infectious disease," exactly? FDA has some ideas, but it's looking for public input as well. "According to the statute, 'the term 'qualifying pathogen' means a pathogen identified and listed by the Secretary … that has the potential to pose a serious threat to public health," explained FDA. Legislators identified some of those threats-gram-positive pathogens, multi-drug resistant gram-negative bacteria, multi-drug resistant tuberculosis (TB) and Clostridium difficile (c-diff)-but it's far from an exhaustive list.

FDA said it's now looking to consider new threats as well under a four-part framework. The organism must either be a current threat to public health as a result of its resistance to drugs, be an imminent threat due to growing rates of drug resistance, be highly deadly or dangerous to humans, or be increasingly found in humans while being resistant to drugs.

The agency said it is consulting with infectious disease experts, including those from the Centers for Disease Control and Prevention (CDC) who normally exercise their authority in this area. In addition, it is looking for public input based on three questions:

How should the above four factors be applied to pathogens to determine which are eligible for incentives under the GAIN Act?

Should FDA consider any other factors in making its determinations about incentives?

Which specific pathogens should be eligible for inclusion on FDA's list of qualified infectious diseases?

The hearing will take place on 18 December 2012 starting at 9:00 am at FDA's White Oak campus in Silver Spring, MD.